Display devices continue to increase in resolution while the vast majority of image or video sources still have lower resolutions. Various techniques have evolved to provide higher resolution video images, many of which are referred to as super-resolution, such as multi-frame and self-similarity, or single-frame. However, the texture and details recovered by these methods may have portions that look unnatural, like an oil painting or a plastic object. The details near the edges may be lost, while the edges are very sharp. Colors may change dramatically with no transition.
In the self-similarity process, a higher resolution image results from one or more iterations of matching and scaling patches from an input, lower resolution image to a higher output resolution image. These artifacts result from the nature of the matching process. No perfectly matched patches exist across several or all scaled versions of the input, lower resolution image. Because of the iterative nature of this process, from coarse resolution to fine, if the previously generated image layer does not have good performance, the next layer will not be recovered because the error propagates from layer to layer. The final high resolution layer will look unnatural, most noticeably in texture regions and detail regions near strong edges.